The present invention relates generally to a system for diagnosing an internal combustion engine, gasoline or diesel. More particularly, the present invention relates to an engine diagnostic apparatus for determining the operating state of the engine components or areas and for producing a corrective message for the operator.
The servicing of automotive engines has become increasingly important as public awareness focuses more critically upon safety, oil and gasoline conservation and the effect of automotive emissions on the environment. Servicing has, however, become more and more difficult as automobile engines have become more sophisticated and intricate. This, in turn, substantially increases the cost of engine maintenance and repair.
Automotive test systems for display of engine operating parameters are well known. More sophisticated systems disclose whether an engine parameter is within an established engine specification.
Heretofore, the automotive mechanic interpreted the engine operational data in order to diagnose a faulty engine component. The data pertinent to a particular engine component is, however, accumulated through a series of individual measurements. Thus, the mechanic must recall previously measured data to perform the necessary interpretation and diagnosis. Errors are inherent in such a process and overall effectiveness depends primarily upon the experience and skill of the mechanic.
This problem is further emphasized as engines become more complex. That is, engine component diagnosis requires the consideration and interpretation of more and more operational data, placing an enormous burden upon the mechanic.